Positive o-quinone diazide photoresist containing base copolymer utilizing monomer having anhydride function and further monomer that increases etch resistance

Abstract

An aqueous-alkaline developable photoresist suitable for a lithography in deep ultraviolet light and having a structural resolution in the sub-μm range. The photoresist contains a developable base polymer that comprises anhydride functions that act as solubility-mediating groups and also contains a photo-active component. In addition to being constructed of monomers carrying anhydride groups, the base polymer can be constructed of further monomers that produce designationally defined properties in the photoresist, for example, exhibit resistance to plasma etching processes. The photoresist of the present invention is therefore very versatile.

We claim: 
     
       1. An aqueous-alkaline developing positive photoresist for producing structures in the sub-μm range having a base polymer which is a copolymer of a monomer comprising an anhydride function and further monomers and a photoactive constituent that is contained in a proportion of 2 through 25% by weight in the photoresist and which comprises o-quinone diazide, wherein the further monomers are silicon-organic and tin-organic compounds that increase the etching resistance of the photoresist to oxygen-containing etching plasma and contain a compound chosen from the group consisting of silicon and tin and have at least one of the following structures: ##STR16## wherein: ≦ n≦3; R 3  through R 5  independently of each other are chosen from the group consisting of an alkyl, aryl, alkoxy, aryloxy, or arylalkylradical;   R 6  is H or alkyl;   Y is for O or NH; and   X is Si or Sn,   whereby a layer of the photoresist is exposed image-wise with radiation around the deep ultraviolet light (DUV) range and is then developed with an aqueously-alkaline medium which additionally contains 0.01 through 10% by weight ammonia or a primary or secondary amine, and whereby the resist layer exhibits low dark erosion up to 0.5% of the layer thickness of the resist layer after development.   
     
     
       2. The photoresist of claim 1 wherein the base polymer is derived from anhydride monomers chosen from the group consisting of: ##STR17## wherein: R 9  and R 10  are chosen from the group consisting of H and alkyl; and R 11  is chosen from the group consisting of alkyl and aryl.   
     
     
       3. The photoresist of claim 1 wherein the base polymer is an alternating copolymer having maleic acid anhydride and allyl trimethylsilane units. 
     
     
       4. The photoresist of claim 3 wherein the mole weight of the base polymer lies between approximately 1000 to about 100000. 
     
     
       5. The photoresist of claim 3 wherein the mole weight of the base polymer lies between approximately 1500 to about 10000. 
     
     
       6. An aqueous-alkaline developing positive photoresist for producing structures in the sub-μm range having a base polymer which is a copolymer of a monomer comprising an anhydride function and further monomers and a photoactive constituent that is contained in a proportion of 2 through 25% by weight in the photoresist and which comprises o-quinone diazide, wherein the further monomers are aromatic compounds that increase the etching resistance of the photoresist to etching plasmas and are selected from the group of compounds having the following structural formulas: ##STR18## wherein R 1  and R 2  independently are selected from the group consisting of H, alkyl, aryl, and halogen, and whereby a layer of the photoresist is exposed image-wise with radiation around the deep ultraviolet (DUV) range and is then developed with an aqueously-alkaline medium which additionally contains 0.01 through 10% by weight ammonia or a primary or secondary amine, and whereby the resist layer exhibits low dark erosion up to 0.5% of the layer thickness of the resist layer after development. 
     
     
       7. The photoresist of claim 6 wherein the base polymer is derived from anhydride monomers chosen from the group consisting of: ##STR19## wherein R 9  and R 10  are chosen from the group consisting of H and alkyl; and R 11  is chosen from the group consisting of alkyl and aryl.